The Finnish patent 87438 discloses an apparatus which utilizes a count object (article) for packaging envelopes in batches of a certain size, the count object (article) being pushed out at fixed spaces when feeding the envelopes into a continuous stack advancing on a conveyor and having the envelopes in a vertical plane. This type of apparatus is also known from the U.S. Pat. No. 3,562,775. The principle in these solutions is the use of a special detector for detecting the arrival of the count object in a separation zone, followed by pushing an elongated separator element through the entire width of the stack transversely to the stack advancing direction for separating from the leading end of the stack a stack portion of a certain size, which is pushed aside for further processing in the operation of packaging the same.
A gap is formed by means of the separator element preferably between the counting object and the leading end of a stack in front of it. In order to separate this stack portion to form a distinctly detached unit, the separator element must produce a sufficiently clear gap. The prior art solutions have employed separator elements which penetrate into a stack through its entire width. In addition, the Finnish patent 87438 discloses a solution in which the separator element is further divided into two horizontal blades for supporting the stack both in the upper and lower part. This ensures that the stack portion remains well separated as the conveyor pushes a continuous stack into the separation zone.